Coated articles are known in the art. Coated articles have been used, for example, in window applications such as insulating glass (IG) window units, vehicle windows, and/or the like.
In certain situations, designers of coated articles often strive for a combination of desirable visible transmission, desirable color values, high light-to-solar gain (LSG, which is equal to visible transmission (Tvis) divided by solar heat gain coefficient (SHGC)) values, low-emissivity (or low-emittance), low SHGC values, and low sheet resistance (Rs). High visible transmission, for example, may permit coated articles to be more desirable in certain window applications. Low-emissivity (low-E), low SHGC, high LSG, and low sheet resistance characteristics, for example, permit such coated articles to block significant amounts of IR radiation from passing through the article. For example, by reflecting IR radiation, it is possible to reduce undesirable heating of vehicle or building interiors.
When light passes through a coated article, however, the perceived color is not always “true” to the original, e.g., because the incident external light is modified by the film or substrate of the window. The color change oftentimes is angularly dependent. Indeed, in conventional coated articles that include low-E coatings, angular color oftentimes is sacrificed to obtain high LSG.
It will be appreciated that it oftentimes would be desirable to help ensure that transmitted color rendering is true, and/or to reduce the severity of or possibly even completely eliminate the tradeoff between angular coloration and LSG. Certain example embodiments address these and/or other concerns.
The field of “metamaterials” is an emerging technology area and is seen as a way to enable certain new technologies. Some efforts have been made to use such materials in a variety of applications such as, for example, in satellite, automotive, aerospace, and medical applications. Metamaterials also have started to show some promise in the area of optical control.
Unfortunately, however, the use of metamaterials in optical control coatings and the like has been plagued by losses related to undesirable surface plasmon resonances or polaritons and can lead to thermal gain. In this regard, and as is known to those skilled in the art, the resonance wavelength is the wavelength at which the metamaterial exhibits surface plasmon resonance. It is typically accompanied by a dip in transmittance and an increase of reflectivity.
Certain example embodiments have been able to overcome these problems associated with the use of metamaterials in optical control coatings. For example, certain example embodiments use a combination of a high index dielectric and a noble metal, which together create a desirable resonance. In this regard, modelling data has indicated a resonance in the near infrared (NIR) spectrum (e.g., from about 700-1400 nm) is sufficient to control angular coloration, as well as improvement in LSG. Metamaterials thus may be used in low-E coatings, and layers may be deposited using sputtering or other technologies.
It will be appreciated that the metamaterial-inclusive layers described herein include discontinuous features with individual length scales longer than individual molecules and atoms but shorter than the wavelength of light (typically in the 10-300 nm range), and having a synthetic structure that exhibits properties not usually found in natural materials. In certain example embodiments, layers comprising discontinuous deposits of sub-wavelength size metal islands are provided, with the sub-wavelength size being for example less than the shortest visible wavelength (e.g., less than about 380 nm). It will be appreciated that the properties not usually found in natural materials that pertain to certain example embodiments may include, for example, the desirable resonances and angular coloration discussed herein, creation of colored transmission to simulate a tinted substrate (e.g., consistently across a wide range of viewing angles), creation of color or visual acuity enhancing effects such as might be used with sunglasses where particular visible ranges of wavelengths are selectively absorbed, etc.
In certain example embodiments, a coated article is provided. A substrate supports a multi-layer low-emissivity (low-E) coating. The multi-layer low-E coating comprises: a plurality of sub-stacks, with each said sub-stack including, in order moving away from the substrate, a barrier layer, a lower contact layer comprising zinc oxide, a continuous and uninterrupted layer comprising Ag over and directly contacting the layer comprising zinc oxide, and an upper contact layer over and directly contacting the layer comprising Ag; and a metamaterial-inclusive layer comprising Ag embedded in a matrix of material, with the metamaterial-inclusive layer being closer to the substrate than each of the sub-stacks, and with the Ag in the metamaterial-inclusive layer being discontinuous.
In certain example embodiments, a coated article is provided. A substrate supports a multi-layer low-emissivity (low-E) coating. The multi-layer low-E coating comprises: a plurality of sub-stacks, with each said sub-stack including, in order moving away from the substrate, a barrier layer comprising TiZrOx, a lower contact layer comprising zinc oxide, a continuous and uninterrupted layer comprising Ag over and directly contacting the layer comprising zinc oxide, and an upper contact layer over and directly contacting the layer comprising Ag; and a metamaterial-inclusive layer comprising Ag embedded in a matrix of material. The Ag in the metamaterial-inclusive layer is substantially spherical or ellipsoidal and distributed throughout the matrix material.
In certain example embodiments, a coated article is provided. A substrate supports a multi-layer low-emissivity (low-E) coating. The multi-layer low-E coating comprises: at least one sub-stack including, in order moving away from the substrate, a barrier layer, a lower contact layer comprising zinc oxide, a continuous and uninterrupted layer comprising Ag over and directly contacting the layer comprising zinc oxide, and an upper contact layer over and directly contacting the layer comprising Ag; and a synthetic layer self-assembled by heat treatment, with the synthetic layer comprising discontinuous island-like formations of material embedded in a matrix, with the synthetic layer being closer to the substrate than the at least one sub-stack, and with each said island-like formation having a major distance of 10-300 nm.
In certain example embodiments, a method of making a coated article including a multi-layer low-E coating supported by a glass substrate is provided. The method comprises: forming a plurality of sub-stacks on the substrate, with each said sub-stack including, in order moving away from the substrate, a barrier layer, a lower contact layer comprising zinc oxide, a continuous and uninterrupted layer comprising Ag over and directly contacting the layer comprising zinc oxide, and an upper contact layer over and directly contacting the layer comprising Ag; and forming a metamaterial-inclusive layer comprising Ag embedded in a matrix of material, with the metamaterial-inclusive layer being closer to the substrate than each of the sub-stacks, and with the Ag in the metamaterial-inclusive layer being discontinuous.
In certain example embodiments, a method of making a coated article including a multi-layer low-E coating supported by a glass substrate is provided. The method comprises: forming a plurality of sub-stacks on the substrate, with each said sub-stack including, in order moving away from the substrate, a barrier layer comprising an oxide of Ti and/or Zr, a lower contact layer comprising zinc oxide, a continuous and uninterrupted layer comprising Ag over and directly contacting the layer comprising zinc oxide, and an upper contact layer over and directly contacting the layer comprising Ag; and causing a synthetic layer to self-assemble via heat treatment, with the synthetic layer, once self-assembled, comprising discontinuous island-like formations of material including Ag embedded in a matrix. The Ag in the synthetic layer is substantially spherical or ellipsoidal and distributed throughout the matrix.
In certain example embodiments, a method of making a coated article including a multi-layer low-E coating supported by a glass substrate is provided. The method comprises: forming at least one sub-stack including, in order moving away from the substrate, a barrier layer, a lower contact layer comprising zinc oxide, a continuous and uninterrupted layer comprising Ag over and directly contacting the layer comprising zinc oxide, and an upper contact layer over and directly contacting the layer comprising Ag; and forming a metamaterial-inclusive layer comprising Ag embedded in a matrix of material, with the metamaterial-inclusive layer being closer to the substrate than the at least one sub-stack, and with the Ag in the metamaterial-inclusive layer being discontinuous.
The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.